Coins in a Brimful Glass
A glass filled right to the rim swallows far more coins than anyone expects, and the water rises into a shining dome instead of spilling. One drop of soap ends the trick at once.
What you need
- Small glass
- Saucer or plate
- Water
- A handful of coins
- Dish soap
How to play
- Stand the glass on a saucer and fill it with water right up to the rim.
- Ask your child to guess how many coins will fit before the water spills over.
- Slide the coins in one at a time, edge first, without dropping them.
- Crouch down and look across the rim at the water bulging above the glass.
- Count the coins you managed and write the number down.
- Start again with one drop of dish soap in the water and see how much sooner it spills.
